1. Field of the Invention
The present invention relates to a technology for managing tag information to be stored in a radio-frequency-identification (RFID) tag.
2. Description of the Related Art
Recently, RFID tags have been employed in various fields. Japanese Patent Application Laid-Open No. 2002-337827, for example, disclose affixing an RFID tag to a mail-delivery order to of a mail (or parcels) and tracing the mail based on information in the RFID tag.
In some cases only a tag ID used for identifying an RFID tag is stored in the RFID tag, while in other cases the tag ID and tag information are stored in the RFID tag.
FIG. 9 is a schematic for explaining one example of a conventional art. In this conventional art, a tag ID and tag information are stored in association in a tag server for a plurality of RFID tags, and only a tag ID is stored in each RFID tag. Only one tag information is associated with one tag ID. When a reader/writer reads a tag ID from an RFID tag and transmits the read tag ID to the tag server, the tag server retrieves tag information corresponding to the received tag ID and transmits the retrieved tag information to the reader/writer. However, there are problems that the tag server needs to be prepared and the reader/writer needs to have online access to the tag server when using the RFID tag.
FIG. 10 is a schematic for explaining another example of a conventional technology in which a tag ID and tag information are stored in each RFID tag, and a reader/writer reads tag information directly from the RFID tag. However, a substantial amount of memory needs to be prepared in the RFID tag for storing the tag information so that an RFID tag becomes rather expensive.